869
FXUS63 KTOP 180755
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
255 AM CDT Tue Jun 18 2024

.KEY MESSAGES...

- Shower and thunderstorm chances increase this PM, continue into
early Thursday along a stalled cold front.

- Potential for a few strong to severe storms this evening with
  several inches of rain total through Wednesday, particularly
  across north-central KS.

&&

.DISCUSSION...
Issued at 249 AM CDT Tue Jun 18 2024

A look at water vapor imagery this morning shows an amplified
pattern over the CONUS. Deep troughing is in place over the
western states while very strong ridging is building over the
East Coast. One notable shortwave trough is lifting northeast
across the Northern Plains into southern Canada. At the
surface, a 990 mb low is centered over South Dakota, with a
trailing cold front extending southwest into eastern Colorado.
This front will move into north-central Kansas by this evening.
Ahead of this, a tight pressure gradient continues to keep
rather breezy conditions for mid-June in place. Similar to
yesterday, expecting southerly wind gusts 30-45 mph during the
daytime hours - just slightly below Wind Advisory criteria.

Thunderstorm chances increase late afternoon and early evening
along the cold front as temperatures climb into the low 90s and
ML CIN erodes. Large DCAPE and boundary-parallel shear vectors
will lead to upscale growth rather quickly. Large hail will be
possible with initial cellular convection given steep mid-level
lapse rates and 25 kts of effective shear, but gusty winds
quickly become the main threat as upscale growth occurs. Also
can`t rule out a brief landspout underneath the initial
updrafts, given steep near-surface lapse rates and high
vorticity along the slow moving boundary. But the biggest threat
will likely be the heavy rainfall potential. This risk is
highest late Tuesday evening into Wednesday morning as the front
inches southeast, though some rain and storms will continue
into Thursday morning. PWAT increases to around 1.8" (around the
95th percentile of climatology) by 06z Wednesday and slow storm
movement will increase the potential for storms to sit over the
same area. As is typical with convection, tough to say ahead of
time exactly where the heaviest rain will fall. However the
greatest risk for 1-3" of rain (and locally higher amounts
capable of causing flooding) will be across north-central
Kansas, generally north and west of Manhattan. Rainfall should
be much spottier to the southeast across east-central Kansas,
with current forecast amounts below 0.25" south of I-35. The
rain and clouds will at least keep for a cooler Wednesday,
particularly behind the front across north-central Kansas where
highs may stay in the 70s.

Rain tapers off Thursday morning as the 597 dam H5 ridge over the
East Coast expands westward. This will result in another warming
trend through Saturday. Expecting Saturday to be the warmest day,
with highs in the mid 90s and heat indices approaching or surpassing
the century mark. A shortwave trough moving across the Northern
Plains then brings our next precipitation chances for Saturday
evening/night, as it flattens the ridge and sends another cold front
southeast through the area.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1220 AM CDT Tue Jun 18 2024

South winds will continue through the period, strongest during the
daytime hours at 15-20 kts with gusts to around 30 kts. Ceilings
will stay primarily VFR, though there is still a few hour window
where some SCT to BKN MVFR ceilings will be possible during the
morning, most likely towards KMHK. By late evening, storms will
develop along a front in north-central KS, though this should
stay northwest of KMHK through midnight.

&&

.CLIMATE...
Issued at 250 AM CDT Tue Jun 18 2024

Record Warm Low Temperatures

June 18

               Record        Forecast
Concordia     80 (1953)         72
Topeka        81 (2021)         76

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Reese
AVIATION...Reese
CLIMATE...Montgomery/Reese